(*
   The two units used should come after this message. Uncomment
several write- commands to get a "fully" operational program
rather than this benchmark version. You then also can skip the
Timer unit and the two commands from that unit (TimerOn and
TimerOff) to make the program much smaller (no float math linked
into the program).
*)

program PiCalc;
{ The fastest PI calculator you'll ever find... :) }

{ From bits and pieces picked up mainly from the FidoNet PASCAL
  echo }
{ Collected, optimized, unitized, etc. by Bjorn Felten
  @ 2:203:208 }
{ Public Domain  --  Nov 1994 }
{ Units needed are at the end !! }

uses HugeUtil, Timer;
{ use Crt if you want fast printout on screen }
{ don't if you want to be able to redirekt o/p }

var
    words, number   : longint;
    nin, link, pii, a239    : HugePtr;

procedure ArcCoTan(n : integer; var angle : Huge);
var n2, del, remain : integer;
    positive : boolean;

begin                       { corresp. integer operations }
  ZeroHuge(angle,words);           { angle := 0 }
  ZeroHuge(nin^,words);            { nin   := 0 }
  ZeroHuge(link^,words);           { link  := 0 }
  angle.dat[angle.len] := 1;       { angle := 1 }
  DivHuge(angle,n,angle,remain);   { angle := angle div n }
  n2 := n*n;                       { n2    := n * n }
  del := 1;                        { del   := 1 }
  positive := true;
  CopyHuge(angle,nin^);            { nin   := angle }
  repeat
    DivHuge(nin^,n2,nin^,remain);  { nin   := nin div n2 }
    inc(del, 2);                   { del   := del + 2 }
    positive := not positive;
    DivHuge(nin^,del,link^,remain);{ link  := nin div del }
    if positive then
      AddHuge(angle,link^)         { angle := angle + link }
    else
      SubHuge(angle,link^);        { angle := angle - link }
{ uncomment to see that program is not dead }
{    write(#13,word(del)) }
  until (link^.len <= 1) and (link^.dat[1] = 0);
{  wr